crash-reporter: Collect i915 error state for chrome crashes

Add in the i915 error state as a log file in "chrome" crash reports.  "chrome"
isn't normally reported through crash_reporter, so this will only kick in where
a developer has explicitly changed a machine to report them as such.

Because the output can be quite large (as we saw with udev crash reports), the
log is compressed before uploading.  Although the file attached to the crash
report will have a ".log" extension, it will actually have been gzip'ed.

BUG=chromium-os:36979
TEST=Tested same config with "sleep" command:
crash/reportdetail?reportid=f429dbcaee7494be

Change-Id: I618a4364dcdd751852a69a79452272b7cf5e61f8
Reviewed-on: https://gerrit.chromium.org/gerrit/39271
Commit-Ready: Michael Krebs <mkrebs@chromium.org>
Tested-by: Michael Krebs <mkrebs@chromium.org>
Reviewed-by: Stuart Abercrombie <sabercrombie@chromium.org>
1 file changed
tree: ba9f76c9e4c3d6532d437b9b9d225abd28bbead8
  1. crash_reporter/